1. Field of the Invention
The present invention relates to microfluidic devices and methods.
2. Description of Related Art
Traditional methods for crystal growth and crystallization are highly labor intensive and require significant quantities of material to evaluate and optimize crystal growth conditions. Examples of these methods include the free interface diffusion method (Salemme, F. R. (1972) Arch. Biochem. Biophys. 151:533-539), vapor diffusion in the hanging or sitting drop method (McPherson, A. (1982) Preparation and Analysis of Protein Crystals, John Wiley and Son, New York, pp 82-127), and liquid dialysis (Bailey, K. (1940) Nature 145:934-935).
Presently, the hanging drop method is the most commonly used method for growing macromolecular crystals from solution, especially for protein crystals. Generally, a droplet containing a protein solution is spotted on a cover slip and suspended in a sealed chamber that contains a reservoir with a higher concentration of precipitating agent. Over time, the solution in the droplet equilibrates with the reservoir by diffusing water vapor from the droplet, thereby slowly increasing the concentration of the protein and precipitating agent within the droplet, which in turn results in precipitation or crystallization of the protein.
The process of growing crystals with high diffraction quality is time-consuming and involves trial-and-error experiment on multiple solution variables such as pH, temperature, ionic strength, and specific concentrations of salts, organic additives, and detergents. In addition, the amount of highly purified protein is usually limited, multi-dimensional trials on these solution conditions are unrealistic, labor-intensive and costly.
A few automated crystallization systems have been developed based on the hanging drop methods, for example Cox, M. J. and Weber, P. C. (1987) J. Appl. Cryst. 20:366; and Ward, K. B. et al. (1988) J. Crystal Growth 90:325-339. More recently, systems for crystallizing proteins in submicroliter drop volumes have been described including those described in PCT Publication Nos. WO00/078445 and WO00/060345.
Existing crystallization, such as hanging drop, sitting drop, dialysis and other vapor diffusion methods have the limitation that the material for analysis and the crystallization medium are exposed to the environment for some time. As the volumes of materials decrease, the ratio of surface area to volume ratio varies as the inverse of the radius of the drop. This causes smaller volumes to be more susceptible to evaporation during the initial creation of the correct mixture and during the initial period after the volume has been set up. Typical hanging drop plates can have air volumes of 1.5 milliliters compared to a sample drop size of 3-10 microliters. Moreover, typical methods expose the sample drop to the environment for a duration of seconds to minutes. Small variability in the rate that samples are made can cause significant variations in the production of crystals. Small variations external environment also can cause significant variations in the production of crystals even if the rate that the samples are made is unchanged. Prior methods fail to reduce the problems of convection currents under 1 g such as those described in U.S. Pat. No. 4,886,646, without the large expenditure of resources or in methods that complicate crystal analysis.
The present invention relates to various microfluidics devices, methods, and kits.
In one embodiment, a microfluidic device is provided that comprises: a card shaped substrate having first and second opposing faces; one or more microvolumes at least partially defined by a first face of the card shaped substrate; and one or more grooves at least partially defined by a second face of the card shaped substrate; wherein a lateral footprint of at least a portion of the one or more grooves overlaps with a lateral footprint of at least one of the one or more microvolumes.
Optionally, the one or more grooves are sufficiently deep relative to the second face of the substrate within the overlapping lateral footprint that when the portion of the microvolume within the overlapping lateral footprint comprises a crystallization sample and an x-ray beam traverses the card shaped substrate at the overlapping lateral footprint, the portion of the microvolume that the x-ray beam traverses contains at least half as many electrons as is contained in the substrate where the x-ray beam traverses. Optionally, the portion of the microvolume that the x-ray beam traverses contains at least as many electrons as is contained in the substrate where the x-ray beam traverses. Preferably, the portion of the microvolume that the x-ray beam traverses contains at least three, five, ten times or more times as many electrons as is contained in the substrate where the x-ray beam traverses.
Optionally, the one or more microvolumes comprise at least one lumen. In such an instance, the groove may have a longitudinal axis that is aligned with a longitudinal axis of the lumen adjacent the overlapping lateral footprint. The groove may also have a longitudinal axis that is perpendicular to a longitudinal axis of the lumen adjacent the overlapping lateral footprint.
In another embodiment, a microfluidic device is provided that comprises: a card shaped substrate having first and second opposing faces; a plurality of microvolumes at least partially defined by a first face of the card shaped substrate; and one or more grooves at least partially defined by a second face of the card shaped substrate; wherein a lateral footprint of at least a portion of the one or more grooves overlaps with lateral footprints of plurality of microvolumes.
In another embodiment, a method is provided for use with a microfluidic device, the method comprising: performing an experiment in a microfluidic device comprising a card shaped substrate having first and second opposing faces, one or more microvolumes at least partially defined by a first face of the card shaped substrate; and one or more grooves at least partially defined by a second face of the card shaped substrate; wherein a lateral footprint of at least a portion of the one or more grooves overlaps with a lateral footprint of at least one of the one or more microvolumes; and performing a spectroscopic analysis within the overlapping lateral footprint. Optionally, the microfluidic device comprises a card shaped substrate.
In another embodiment, a method is provided for use with a microfluidic device, the method comprising: performing an experiment in a microvolume of a microfluidic device; and performing a spectroscopic analysis using an x-ray beam that traverses the microfluidic device such that material within the microfluidic device that the x-ray beam traverses contains at least as many electrons as is otherwise traversed when the x-ray beam traverses the microfluidic device. Optionally, the material within the microfluidic device that the x-ray beam traverses contains at least three, five, ten times or more times as many electrons as is otherwise traversed when the x-ray beam traverses the microfluidic device.
In another embodiment, a method is provided for determining crystallization conditions for a material, the method comprising: taking a plurality of different crystallization samples in an enclosed microvolume, the plurality of crystallization samples comprising a material to be crystallized and crystallization conditions which vary among the plurality of crystallization samples; allowing crystals of the material to form in the plurality of crystallization samples; and identifying which of the plurality of crystallization samples comprise a precipitate, oil or a crystal of the material. One or more dividers may optionally be positioned between different crystallization samples in enclosed microvolume to separate adjacent crystallization samples.
In another embodiment, a method is provided for determining crystallization conditions for a material, the method comprising: taking a plurality of different crystallization samples in a plurality of enclosed microvolumes, each microvolume comprising one or more crystallization samples, the crystallization samples comprising a material to be crystallized and crystallization conditions that vary among the plurality of crystallization samples; allowing crystals of the material to form in plurality of crystallization samples; and identifying which of the plurality of crystallization samples comprise a precipitate, oil or a crystal of the material. One or more dividers may optionally be positioned between different crystallization samples in the enclosed microvolumes to separate adjacent crystallization samples.
In another embodiment, a method is provided for determining crystallization conditions for a material, the method comprising: taking a microfluidic device comprising one or more lumens having microvolume dimensions and a plurality of different crystallization samples within the one or more lumens, the plurality of crystallization samples comprising a material to be crystallized and crystallization conditions that vary among the plurality of crystallization samples; transporting the plurality of different crystallization samples within the lumens; and identifying a precipitate or crystal formed in the one or more lumens. Transporting the plurality of different crystallization samples within the one or more lumens may be performed by a variety of different methods. For example, transporting may be performed by a method selected from the group consisting of electrophoresis, electroosmotic flow and physical pumping. In one variation, transporting is performed by electrokinetic material transport.
In a variation according to this embodiment, at least one of the lumens optionally comprises a plurality of different crystallization samples. One or more dividers may be positioned between different crystallization samples in at least one of the lumens to separate adjacent crystallization samples.
Also according to this embodiment, the method may further comprise forming the plurality of different crystallization samples within the one or more lumens. The plurality of crystallization samples may be comprised in a single lumen or a plurality of lumens.
In another embodiment, a method is provided for determining crystallization conditions for a material, the method comprising: taking a microfluidic device comprising one or more lumens having microvolume dimensions and a plurality of different crystallization samples within the one or more lumens, the plurality of crystallization samples comprising a material to be crystallized and crystallization conditions that vary among the plurality of crystallization samples; transporting the plurality of different crystallization samples within the one or more lumens; and identifying a precipitate or crystal formed in the one or more lumens; and performing a spectroscopic analysis on the identified precipitate or crystal while within the lumen.
The method may optionally further include forming the plurality of different crystallization samples within the one or more lumens. The plurality of crystallization samples may be comprised in a single lumen or multiple lumens.
In another embodiment, a microfluidic method is provided comprising: delivering a first fluid to a first lumen of a microfluidic device and a second, different fluid to a second lumen of the microfluidic device, the first and second lumens sharing a common wall that allows for diffusion between the lumens over at least a portion of the length of the lumens; and having the first and second fluids diffuse between the first and second lumens.
In one variation according to this method, a composition of at least one of the first and second fluids is varied so that the composition of at least one of the first and second fluids varies along a length of the lumen.
In another variation according to this method, the composition of at least one of the first and second fluids varies over time as it is delivered to the lumen so that the fluid forms a gradient with regard to a concentration of at least one component of the fluid that changes along a length of the lumen.
In another variation according to this method, the microfluidic device comprises a plurality of first and second lumens, the method comprising delivering first and second fluids to each of the plurality of first and second lumens.
In yet another variation according to this method, the same first and second fluids are delivered to each of the plurality of first and second lumens.
In yet another variation according to this method, different first and second fluids are delivered to the plurality of first and second lumens.
It is noted that the first and second fluids may have a same or different flow rate within the lumen. It is also noted that the first and second fluids may each optionally comprise more than one different fluid flow. The first and second fluids may also each optionally comprise dividers that separate the fluid into a plurality of aliquots separated by the dividers.
In another variation according to this method, the method optionally further comprises delivering a third fluid to a third lumen which shares a common wall with at least one of the first and second lumens, the common wall allowing for diffusion between the third lumen and the first or second lumen over at least a portion of the length of the lumens.
In another embodiment, a microfluidic device is provided that comprises: a substrate; a first lumen at least partially defined by the substrate; and a second lumen; wherein the first and second lumens share a common wall with each other that allows for diffusion between the two lumens over at least a portion of the length of the two lumens. The common wall may optionally comprise a membrane, gel, frit, or matrix that allows for diffusion between the two lumens.
Also according to this embodiment, the device may further comprise a third lumen, the third lumen sharing a common wall with at least one of the first and second lumens so as to allow for diffusion between the lumens over at least a portion of the length of the lumens.
In another embodiment, a microfluidic device is provided that comprises: a substrate; a plurality of sets of lumens, each set comprising a first lumen at least partially defined by the substrate, and a second lumen, wherein the first and second lumens share a common wall with each other that allows for diffusion between the two lumens over at least a portion of the length of the two lumens. The common wall may optionally comprise a membrane, gel, frit, or matrix that allows for diffusion between the two lumens.
According to this embodiment, the device may further comprise a third lumen, the third lumen sharing a common wall with at least one of the first and second lumens so as to allow for diffusion between the lumens over at least a portion of the length of the lumens.
Also according to this embodiment, the device may optionally comprise at least 4, 8, 12, 24, 96, 200, 1000 or more sets of lumens.
A variety of different devices and methods are also provided that use centrifugal force to cause fluid movement within a microfluidic device.
In one embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a plurality of microvolumes; and causing movement of material in a same manner within the plurality of microvolumes by applying centrifugal forces to the material.
In another embodiment, a microfluidic method is provided that comprises: taking a plurality of microfluidic devices, each device comprising a plurality of microvolumes; and causing movement of material in a same manner within the plurality of microvolumes of the plurality of devices by applying centrifugal forces to the material. Optionally, a same centrifugal force is applied to each of the plurality of devices.
In a variation, the plurality of microfluidic devices may be stacked relative to each other when the centrifugal forces are applied. The plurality of microfluidic devices may also be positioned about a rotational axis about which the plurality of microfluidic devices are rotated to apply the centrifugal forces.
In another embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a plurality of microvolumes; and physically moving the device so as to effect a same movement of material within the plurality of microvolumes. Physically moving the device preferably causes centrifugal force to be applied, for example, by rotation of the device about an axis.
According to this embodiment, the material moved in each of the plurality of microvolumes by movement of the device preferably has a same quantity.
In another embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a plurality of microvolumes; and accelerating or decelerating a motion of the device so as to effect a same movement of material within the plurality of microvolumes. According to this embodiment, the motion of the device is optionally a rotation of the device. In such instances, acceleration or deceleration may be caused by a change in a rate of rotation of the device.
In another embodiment, a microfluidic device is provided that comprises: a substrate; and a plurality of microvolumes at least partially defined by the substrate, each microvolume comprising a first submicrovolume and a second submicrovolume that is in fluid communication with the first submicrovolume when the device is rotated, the plurality of microvolumes being arranged in the device such that fluid in the first submicrovolumes of multiple of the microvolumes are transported to second submicrovolumes of the associated microvolumes when the device is rotated.
According to this embodiment, the device may be designed so that at least 4, 8, 12, 36, 96, 200, 1000 or more of the microvolumes are transported to second submicrovolumes of the associated microvolumes when the device is rotated.
Also according to this embodiment, the device may be designed so that the volume of fluid delivered from the first submicrovolume to the second submicrovolume of a given microvolume upon rotation of the device is within 50%, 25%, 10%, 5%, 2%, 1% or less of the volume of fluid delivered from the first submicrovolumes to the second submicrovolumes of any other microvolumes when a same volume of fluid is added to the first submicrovolumes.
In another embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a substrate, and a plurality of microvolumes at least partially defined by the substrate, each microvolume comprising a first submicrovolume and a second submicrovolume where the first submicrovolume and second microvolume are in fluid communication with each other when the device is rotated; adding fluid to a plurality of the first submicrovolumes; and rotating the device to cause fluid from the plurality of first submicrovolumes to be transferred to the second submicrovolumes in fluid communication with the first submicrovolumes.
According to this embodiment, the device may be designed so that at least 4, 8, 12, 24, 96, 200, 1000 or more of the microvolumes are transported to second submicrovolumes of the associated microvolumes when the device is rotated.
Also according to this embodiment, the device may be designed so that the volume of fluid delivered from the first submicrovolume to the second submicrovolume of a given microvolume upon rotation of the device is within 50%, 25%, 10%, 5%, 2%, 1% or less of the volume of fluid delivered from the first submicrovolumes to the second submicrovolumes of any other microvolumes when a same volume of fluid is added to the first submicrovolumes.
Also according to this embodiment, the method may be performed as part of performing an array crystallization trial. The array crystallization trial may involve the crystallization of a variety of different materials including various biomolecules such as proteins.
In another embodiment, a microfluidic method is provided that comprises: taking a plurality of microfluidic devices, each comprising a substrate, and a plurality of microvolumes at least partially defined by the substrate, each sample microvolume comprising a first submicrovolume and a second submicrovolume where the first submicrovolume and second submicrovolume are in fluid communication with each other when the device is rotated; adding fluid to a plurality of the first submicrovolumes in the plurality of microfluidic devices; and rotating the plurality of microfluidic devices at the same time to cause fluid from the plurality of first submicrovolumes to be transferred to the second submicrovolumes in fluid communication with the first submicrovolumes.
According to this embodiment, the plurality of microfluidic devices may optionally be stacked relative to each other during rotation. The plurality of microfluidic devices may also be positioned about a rotational axis about which the plurality of microfluidic devices are rotated. In one variation, the rotational axis about which the plurality of microfluidic devices are rotated is positioned within the lateral footprints of the plurality of microfluidic devices. In another variation, the rotational axis about which the plurality of microfluidic devices are rotated is positioned outside of the lateral footprints of the plurality of microfluidic devices.
In yet another embodiment, a microfluidic device is provided that comprises: a substrate shaped so as to provide the device with an axis of rotation about which the device may be rotated; and a plurality of microvolumes at least partially defined by the substrate, each microvolume comprising a first submicrovolume and a second submicrovolume that is in fluid communication with the first submicrovolume when the device is rotated, the plurality of microvolumes being arranged in the device such that fluid in the first submicrovolumes of multiple of the microvolumes are transported to the second submicrovolumes of the associated microvolumes when the device is rotated about the rotational axis. Optionally, the second microvolumes are lumens.
The device may optionally comprise a mechanism that facilitates the device being rotated about the rotational axis. For example, the substrate may define a groove or hole at the rotational axis that facilitates the device being rotated about the rotational axis. Optionally, a center of mass of the device is at the rotational axis and the substrate defines a groove or hole at the rotational axis that facilitates the device being rotated about the rotational axis. In one variation, the device is disc shaped, the substrate defining a groove or hole at the rotational axis of the disc that facilitates the device being rotated about the rotational axis.
Also according to this embodiment, the method may be performed as part of performing an array crystallization trial. The array crystallization trial may involve the crystallization of a variety of different materials including various biomolecules such as proteins.
In another embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a substrate, and a plurality of microvolumes at least partially defined by the substrate, each microvolume comprising a first and a second submicrovolume where the first and second submicrovolumes are in fluid communication with each other when the device is rotated about a rotational axis of the device; adding fluid to a plurality of the first submicrovolumes; and rotating the device about the rotational axis of the device to cause fluid in the first submicrovolumes to be transferred to the second submicrovolumes.
Also according to this embodiment, the method may be performed as part of performing an array crystallization trial. The array crystallization trial may involve the crystallization of a variety of different materials including various biomolecules such as proteins.
In another embodiment, a microfluidic device is provided that comprises: a substrate; one or more microvolumes at least partially defined by the substrate, each microvolume comprising a first submicrovolume, a second submicrovolume where fluid in the first submicrovolume is transported to the second submicrovolume when the device is rotated about a first rotational axis, and a third submicrovolume where fluid in the first submicrovolume is transported to the third submicrovolume when the device is rotated about a second, different rotational axis. The device itself include features to facilitate the rotation of the device about one or more rotational axes. The device may alternative be rotated about one or more rotational axes by the use of an external fixture.
In another embodiment, a microfluidic device comprising: a substrate; one or more microvolumes extending along a plane of the substrate, each microvolume comprising a first submicrovolume, a second submicrovolume where fluid in the first submicrovolume is transported to the second submicrovolume when the device is rotated about a first rotational axis that is positioned further away from the second submicrovolume than the first submicrovolume, and a third submicrovolume where fluid in the first submicrovolume is transported to the third submicrovolume when the device is rotated about a second, different rotational axis that is positioned further away from the third submicrovolume than the first submicrovolume. Optionally, the substrate is card shaped. In such instances, the one or more microvolumes may optionally extend along a surface of the card shaped substrate.
In another embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a substrate and a plurality of microvolumes at least partially defined by the substrate, each microvolume comprising an first submicrovolume, a second submicrovolume where fluid in the first submicrovolume is transported to the second submicrovolume when the device is rotated about a first rotational axis, and a third submicrovolume where fluid in the first submicrovolume is transported to the third submicrovolume when the device is rotated about a second, different rotational axis; adding fluid to the first submicrovolumes of the microvolumes; and in any order rotating the device about the first and second rotational axes to cause fluid from the first submicrovolumes to be transferred to the second and third submicrovolumes.
It is noted that the method may be performed as part of performing an array crystallization trial. The array crystallization trial may involve the crystallization of a variety of different materials including various biomolecules such as proteins.
In another embodiment, a microfluidic device is provided that comprises: a substrate; and a plurality of microvolumes at least partially defined by the substrate, each microvolume comprising a first submicrovolume and a second submicrovolume in fluid communication with the first submicrovolume when the device is rotated about a first rotational axis, wherein rotation of the device about the first rotational axis causes a fixed volume to be transported to each of the second submicrovolumes.
According to this embodiment, the plurality of microvolumes may optionally further comprise one or more outlet submicrovolumes in fluid communication with the first submicrovolume.
Also according to this embodiment, the plurality of microvolumes may optionally further comprise one or more outlet submicrovolumes where fluid in the first submicrovolume not transported to the second submicrovolume when the device is rotated about a first rotational axis is transported to one or more one or more outlet submicrovolumes when the device is rotated about a second, different rotational axis.
In another embodiment, a microfluidic device is provided that comprises: a substrate; a first microvolume at least partially defined by the substrate comprising a first submicrovolume; a second submicrovolume where fluid in the first submicrovolume is transported to the second submicrovolume when the device is rotated about a first rotational axis; and a second microvolume at least partially defined by the substrate comprising a third submicrovolume; a fourth submicrovolume where fluid in the third submicrovolume is transported to the fourth submicrovolume when the device is rotated about the first rotational axis; and wherein fluid in the second and fourth submicrovolumes are transported to a fifth submicrovolume where the second and fourth submicrovolumes are mixed when the device is rotated about a second, different rotational axis.
According to this embodiment, the fifth submicrovolume may optionally be in fluid communication with the second and fourth submicrovolumes via the first and third submicrovolumes respectively.
Also according to this embodiment, the device may further comprise one or more outlet submicrovolumes in fluid communication with the first and third submicrovolumes.
Also according to this embodiment, the device may further comprise one or more outlet submicrovolumes in fluid communication with the first and second submicrovolumes where fluid in the first and third submicrovolumes not transported to the second and fourth submicrovolumes when the device is rotated about the first rotational axis is transported to one or more one or more outlet submicrovolumes when the device is rotated about a third, different rotational axis.
Also according to this embodiment, the device may further comprise at least 4, 8, 12, 24, 96, 200, 1000, or more pairs of first and second microvolumes.
Also according to this embodiment, the device may be designed such that the volume of fluid transported to any given second submicrovolume does not deviate from the volume of fluid transported to another second submicrovolume by more than 50%, 25%, 10%, 5%, 2%, 1% or less.
The device may also optionally be designed so that any of the following conditions are satisfied: the first rotational axis is positioned further away from the second and fourth submicrovolumes than the first and third submicrovolumes; the first rotational axis about which the microfluidic device is designed to be rotated is positioned within a lateral footprint of the microfluidic device; and the first rotational axis about which the microfluidic device is designed to be rotated is positioned outside of a lateral footprint of the microfluidic device.
In yet another embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a substrate, and a plurality of microvolumes at least partially defined by the substrate, each microvolume comprising a first submicrovolume and a second submicrovolume in fluid communication with the first submicrovolume; adding fluids to the first submicrovolumes; and applying a centrifugal force to the device to cause a same volume of fluid to be transported to the second microvolumes from the first submicrovolumes.
Optionally, the microvolumes may further comprise an outlet submicrovolume in fluid communication with the first submicrovolumes. In such instances, the method may further comprise transporting fluid in the first submicrovolume to the outlet submicrovolume that was not transported to the second submicrovolume when the centrifugal force was applied. The method may also further comprise transporting fluid in the first submicrovolume to the outlet submicrovolume that was not transported to the second submicrovolume when the device is rotated about a first rotational axis by rotating the device about a second, different rotational axis.
Also according to the embodiment, the device may be designed such that the volume of fluid transported to any given second submicrovolume does not deviate from the volume of fluid transported to another second submicrovolume by more than 50%, 25%, 10%, 5%, 2%, 1% or less.
In another embodiment, a microfluidic method is provided that comprises: taking a microfluidic device comprising a substrate, a first microvolume at least partially defined by the substrate comprising a first submicrovolume and a second submicrovolume where fluid in the first submicrovolume is transported to the second submicrovolume when the device is rotated about a first rotational axis, and a second microvolume at least partially defined by the substrate comprising a third submicrovolume and a fourth submicrovolume where fluid in the third submicrovolume is transported to the fourth submicrovolume when the device is rotated about the first rotational axis, the microvolumes further comprising a fifth submicrovolume where fluid in the second and fourth submicrovolumes are mixed when the device is rotated about a second, different rotational axis; adding a first fluid to the first submicrovolume and a second fluid to the third submicrovolume; rotating the device about the first rotational axis to transport the first and second fluids to the second and fourth submicrovolumes; and rotating the device about the second rotational axis to transport the first and second fluids from the second and fourth submicrovolumes to the fifth submicrovolume.
In one variation, the fifth submicrovolume is in fluid communication with the second and fourth submicrovolumes via the first and third submicrovolumes respectively.
Optionally, the method further comprises removing fluid from the first and third submicrovolumes that is not transported to the second and fourth submicrovolumes prior to rotating the device about the second rotational axis.
Also according to the embodiment, the device may comprise a plurality of pairs of first and second microvolumes and the volume of fluid transported to any given second submicrovolume does not deviate from the volume of fluid transported to another second submicrovolume by more than 50%, 25%, 10%, 5%, 2%, 1% or less.
In another embodiment, a microfluidic method is provided that comprises: delivering first and second fluids to a lumen of a microfluidic device such that the first and second fluids flow adjacent to each other within the lumen without mixing except for diffusion at an interface between the first and second fluids, wherein the first fluid is different than the second fluid.
According to this embodiment, the composition of at least one of the first and second fluids is optionally varied over time as it is delivered to the lumen so that the fluid forms a gradient with regard to a concentration of at least one component of the fluid that changes along a length of the lumen.
According to this embodiment, the microfluidic device may comprise a plurality of lumens, the method optionally comprising delivering first and second fluids to each of the plurality of lumens.
According to this embodiment, the same first and second fluids may be delivered to each of the plurality of lumens. Alternatively, different first and second fluids are delivered to the different lumens of the plurality of lumens. The first and second fluids may also have a same or different flow rate within the lumen.
Also according to this embodiment, the first and second fluids may be combined to form different crystallization conditions for crystallizing a molecule such as a protein.
In another embodiment, a microfluidic method is provided that comprises: delivering first and second fluids to a lumen of a microfluidic device such that the first and second fluids flow adjacent to each other within the lumen without mixing except for diffusion at an interface between the first and second fluids, wherein the first fluid is different than the second fluid and a composition of at least one of the first and second fluids delivered to the lumen is varied so that the composition of at least one of the first and second fluids within the lumen varies along a length of the lumen.
In yet another embodiment, a microfluidic method is provided that comprises: delivering first, second and third fluids to a lumen of a microfluidic device such that the first, second and third fluids flow adjacent to each other within the lumen without mixing except for diffusion at an interface between the first, second and third fluids, wherein the first, second and third fluids are different than each other and a composition of at least one of the first, second and third fluids delivered to the lumen is varied so that the composition of at least one of the first, second, and third fluids within the lumen varies along a length of the lumen.
According to this embodiment, the composition of at least one of the first, second and third fluids may be varied over time as it is delivered to the lumen so that the fluid forms a gradient with regard to a concentration of at least one component of the fluid that changes along a length of the lumen.
Also according to this embodiment, the microfluidic device may comprise a plurality of lumens, the method comprising delivering first, second and third fluids to each of the plurality of lumens.
The same or different first, second and third fluids may be delivered to each of the plurality of lumens. Optionally, at least one of the first, second and third fluids have a different flow rate than another of the fluids within the lumen. Also, at least one of the first, second and third fluids may have the same flow rate than another of the fluids within the lumen.
Also according to this embodiment, the first, second and third fluids may be combined to form different crystallization conditions for crystallizing a molecule such as a protein. In one variation, the first, second and third fluids combine to form different crystallization conditions, the second fluid comprising the material to be crystallized and being positioned between the first and third fluids.
In regard to the various embodiments where a device is rotated about one or more rotational axes, the device may optionally be designed so that any or more of the following conditions are satisfied: the first and second rotational axes are laterally offset relative to each other; the first and second rotational axes are at an angle relative to each other and intersect; the first and second rotational axes are at an angle relative to each other and are laterally offset; the first and second rotational axes are perpendicular to each other and intersect; the first and second rotational axes are perpendicular to each other and are laterally offset; the first and second rotational axes are at an angle of 45 degrees relative to each other and intersect; the first and second rotational axes are at an angle of 45 degrees relative to each other and are laterally offset; and the first and second rotational axes are parallel and laterally offset relative to each other.
According to any of the embodiments employing centrifugal forces, the devices may be designed so that material is optionally moved within at least 4, 8, 12, 24, 96, 200, 1000 or more different microvolumes in a same manner when the centrifugal forces are applied.
Also according to any of the embodiments employing centrifugal forces, the devices may be designed so that the volume of fluid or other material delivered to a submicrovolume in a given microvolume is within 50%, 25%, 10%, 5%, 2%, 1% or less of the volume of fluid or other material delivered to a corresponding submicrovolume in any other microvolume Optionally, the centrifugal forces are applied such that a same centrifugal force is applied to material in each of the plurality of microvolumes.
Optionally, the centrifugal forces are applied such that at least 0.01 g, 0.1, 1 g, 10 g, 100 g or more force is applied to the material in the device to cause the material to move within the microvolumes.
Applying the centrifugal forces may be performed by rotating the device. Optionally, the centrifugal forces are applied by rotating the device at least 10 rpm, 50 rpm, 100 rpm or more.
In regard to all of the above embodiments, unless otherwise specified, microvolumes may have a variety of shapes including, but not limited to lumens and microchambers. When a lumen is employed, the lumen optionally has a cross sectional diameter of less than 2.5 mm, optionally less than 1 mm, and optionally less than 500 microns.
A variety of different substrates may be used to make the microfluidic devices of the present invention. In one variation, the substrate comprises one or more members of the group consisting of polymethylmethacrylate, polycarbonate, polyethylene terepthalate, polystyrene, styrene copolymers, glass, and fused silica. In one variation, the substrate is optically transparent.
According to each of the above embodiments, the experiment being performed may optionally be a crystallization of a molecule or material. The crystallization may optionally be of a biomolecule. Examples of biomolecules that may be crystallized include, but are not limited to viruses, proteins, peptides, nucleosides, nucleotides, ribonucleic acids, and deoxyribonucleic acids.
It is also noted that the material to be crystallized may contain one, two or more materials selected from the group consisting of viruses, proteins, peptides, nucleosides, nucleotides, ribonucleic acids, deoxyribonucleic acids, small molecules, drugs, putative drugs, inorganic compounds, metal salts, organometallic compounds and elements. In one variation, the material to be crystallized is a macromolecule with a molecular weight of at least 500 Daltons.
In certain embodiments, a spectroscopic analysis is performed. The spectroscopic analysis may optionally be selected from the group consisting of Raman, UV/VIS, IR, x-ray spectroscopy, polarization, and fluorescent. In one particular variation, the spectroscopic analysis is x-ray spectroscopy. In a further particular variation, the x-ray spectroscopy is x-ray diffraction.
In some instances, the spectroscopic analysis involves an x-ray traversing the microfluidic device. In such instances, a groove may be employed in the device that is sufficiently deep relative to the second face of the substrate within the overlapping lateral footprint that when the portion of the microvolume within the overlapping lateral footprint comprises a crystallization sample and an x-ray beam traverses the card shaped substrate at the overlapping lateral footprint, the portion of the microvolume that the x-ray beam traverses contains at least half as many electrons as is contained in the substrate where the x-ray beam traverses. Optionally, the portion of the microvolume that the x-ray beam traverses contains at least as many electrons as is contained in the substrate where the x-ray beam traverses. Preferably, the portion of the microvolume that the x-ray beam traverses contains at least three, five, ten times or more times as many electrons as is contained in the substrate where the x-ray beam traverses.
Each of the above embodiments may optionally include transporting material within the microfluid device. Such transport may be performed by a variety of different methods. For example, transporting may be performed by a method selected from the group consisting of electrophoresis, electroosmotic flow and physical pumping. In one variation, transporting is performed by electrokinetic material transport. In some instances, transporting is performed by moving the device. This may be done by applying a centrifugal force, which in turn may be performed by rotating the device about a rotational axis.
Each of the above embodiments may optionally include the use of one or more dividers to separate aliquots of materials. In some instances, the separated aliquots of materials correspond to separate experiments such as crystallization trials. The dividers may be formed of a variety of different materials. For example, the dividers may be formed of a permeable, semi-permeable or impermeable material that may be a gas, liquid, gel, or solid. In one particular variation, the one or more dividers are selected from the group consisting of a membrane, gel, frit, and matrix.
The one or more dividers may form various interfaces including those selected from the group consisting of liquid/liquid, liquid/gas interface, liquid/solid and liquid/sol-gel interface.
The one or more dividers optionally function to modulate diffusion characteristics between adjacent crystallization samples. For example, the one or more dividers may be formed of a semi-permeable material that allows diffusion between adjacent crystallization samples.
These and other methods, devices, compositions and kits are described herein.